Powek transmission



Feb. 29, 1944. Ej F. WEB 2,342,712

POWER TRANSMI SS ION Original Filed Sept. 27, 1940 3 Sheets-Sheet 1 E.29,47%?! F14/d @ge ATTORNEY; i

' Feb. 29, 1944. E;- WEBB' 2,342,712

` POWER' TRANSMISSION Original Filed Spf. 27, 1940 3 Sheets-Sheet' 25471140 ,ffffff A TTORN E YS,

Feb. 29, 1944.l E, F` WEBB -POWER TRANSMISSION original Filed sepf. 27',1940 s sheets-snaai s NVENTOR aha7 We; I i2@ A TTORNE KS.

Patented Feb. 29, 1944 `POWER TRANSMISSION Edmond Ii'.l Webb, FranklinVillage, Mich., assignor to Chrysler Corporation, Highland Park, Mich.,a corporation of Delaware Original application September- Z7, 1940,Serial Divided and this application May 14, 1943,v Serial No. 486,930

8 Claims. (.Cl. I4-472) This invention relates to `motor vehicles andArefers more particularly to power transmission and control mechanismtherefor. i y' My invention has particular reference to transmissionsystems, in which the engine ignition is momentarily interrupted inorder to unload positively engageable drive control elements so as'tofacilitate disengagement of such elements. One example of such aVtransmission is described and claimed inthe copending application ofCarl A. Nerachery et al., Serial No. 335,310, filed May 15, v1940. 'KInsuchv transmission systems, the engine ignition sometimes `is groundedbeyond the desired momentary period either as a characteristic of thetransmission control mechanism, because of failure of the mechnaism toproperly function, or for other reasons. When the ignition system isthus interrupted, usually by grounding the same,fthe engine is oftenrendered inoperative so that the car cannot be driven under its ownpower, or the change speed mechanism does not function properly. v

It is an object of my invention to provide means for remedying theforegoing difficulties whereby the engine ignition is automaticallyrestored after a predetermined time of interruption regardless oftheproper functioning of the ransmission control mechanism which isordinarily provided for momentarily interrupting the ignition system. l

vAnother object is to provide time control means for restoring theengine to normal functioning in the event that the primary engineinterrupting system fails to restore the engine tol f'- normalfunctioning.

A further object is to provide means for lessening the time of ignitioninterruption occasioned by the usual transmission kcontrol mechanism sothat the time ofignition interruption is xed and independent ofthe timerillustrative embodiment thereof, reference being t had to theaccompanying drawings in which:

Fig. l is a side elevational view showing' the motor vehicle engine randpower transmission.

Fig. 2 is a longitudinal sectional elevational view'tlirough the mainclutching mechanism, l

CTI

Fig. 3 is a similar View through the change speed transmission.

Fig. 4 is a detail enlarged view of the blocker clutch as seen in Fig.3.

Fig. 5 is a sectional plan view illustrated as a development accordingto line 5--5 of Fig. 4, the automatic clutching sleeve being released.

Figy is a similar view showing the automatic clutching sleeve in itsintermediate shift position during the drive blocking condition.

Fig; 'l is a similar view showing the automatic clutching sleeve initscoasting relationship from the Fig. 6 showing, the clutching sleevebeing unblocked during coast for its clutching movement.

Fig. 8 is a similar view showing the automatic clutching sleeve in fullclutching engagement.

Fig. 9 is a view similar to Fig. 5 butshowing the automatic clutchingsleeve in its other intermediate shift position during the coastblocking condition.

Fig. 10 is a'diagrammatic view of the control mechanism for theautomatic clutching sleeve, the latter being shown in its releasedposition.

Fig. l1 is a similar view of a portion of the Fig. lil control mechanismin another operating position.

While this control may be employed in conjunction with various types andarrangements of motor vehicle transmissions, in order to illustrate onedriving system the invention is shown in connection with certain salientparts of the aforesaid Neracher et al. application.

In the drawings A represents the internal combustion engine which drivesthrough fluid coupling B and conventional type of friction main clutch Cto the speed ratio transmission D whence the drive passes from outputshaft is to drive the rear vehicle wheels in the usual manner.

vThe engine crankshaft 2l carries the vaned iiuid coupling impeller 22which in the Well known manner drives the vaned runner 23 whence thedrive passes through hub 2s to clutch driving member 25. This memberthen transmits the drive, when clutch C is engaged as in Fig. 2, throughdriven member 26 to the transmission driving shaft 21 carrying the'maindrive pinion 28. A clutch pedal 29 controls clutch C such that when thedriver depresses this pedal, collar 30 is thrust forward to cause levers3|' to release the clutch driving pressure plate 32 against springs 33thereby releasing the drive between runner 23 and shaft 2l. The primaryfunction of the main clutch C is to enable the driver to make manualshifts in transmission D.

Referring to the transmission, pinion 2B is in constant mesh with gear34 which drives countershaft 35 through an overrunning clutch E of theusual type such that when shaft 21 drives in its usual clockwisedirection (looking from front to rear) then clutch E will engage to lockgear 34 to countershaft 35 whenever the gear 34 tends to drive fasterthan the countershaft. However, whenever this gear 34 tends to rotateslower than the oountershaft then clutch E will automatically releasewhereby shaft 21, under certain conditions, may readily drop its speedwhile countershaft 35 continues to revolve.

Countershaft 35 comprises cluster gears 36, 31

and 38 which respectively provide drives in first,

third and reverse. Freely rotatable on shaft 28 are the first and thirddriven gears 39 and 48 respectively in constant mesh with countershaftgears 36 and 31. A hub 4I is splined on shaft 20 and carries therewith amanually shiftable sleeve 42 adapted to shift from the Fig. 3 neutralposition either rearwardly to clutch with teeth 43 of gear 39 or elseforwardly to clutcl' with teeth 44 of gear 48. Sleeve 42 is operablyconnected to shift rail 45 adapted for operation by any suitable meansunder shifting control of the vehicle driver.

Shaft 20 also carries reverse driven gear 4B fixed thereto. A reverseidler gear 41 is suitably mounted so that when reverse drive is desired,idler 41 is shifted into mesh with gears 38 and 46.

First, third and reverse speed ratio drives and neutral are under manualshift control of the vehicle driver, the main clutch C being released bydepressing pedal 29 in shifting into any one cf these drives.

First is obtained by shifting sleeve 42 to clutch with teeth 43, thedrive passing from engine A, through fluid coupling B, clutch C andshaft 21 to pinion 28 thence through gear 34 and clutch E tocountershaft 35. From the countershaft the drive is through gears 36, 39and sleeve 42 to shaft 20.

Third is obtained by shifting sleeve 42 to clutch with teeth 44, thedrive passing from the engine to the countershaft 35 as before, thencethrough gears 31, 40 and sleeve 42 to shaft 28.

Reverse is obtained by shifting idler into mesh with gears 38, 46,sleeve 42 being in neutral, the reverse drive passing from the engine tothe countershaft 35 as before, thence through gears 38, 41 and 45 toshaft 20.

Slidably splined on teeth 48 carried by gear 40 is the automaticclutching sleeve F which., under certain conditions, is adapted to shiftfor wardly to clutch with teeth 49 carried by pinion 28 therebypositively clutching shaft 2.' directly to gear 48. This sleeve F isadapted to step-up the speed ratio drive from first to second and fromthird to fourth which is a direct drive speed ratio. Control means isprovided which limits clutching of sleeve F to approximate synchronismwith teeth 49 and also to a condition of engine coast, sleeve F beingprevented from clutching during that condition known as engine drive aswhen'the engine is being speeded up under power.

When driving in first, second is obtained by the driver releasing theusual-accelerator pedal 59 thereby closing the engine throttle valve andallowing the engine to rapidly coast down. When this occurs, the enginealong with shaft 21, pinion 28 and gear 34 all slow down while shaft 20along with gears 39 and 35 continue their speeds by accommodation ofclutch E which now overruns. The engine slows down until teeth 49 arebrought to approximate synchronism with sleeve F which thereuponautomatically shifts to clutch with teeth 49 resulting in a two-waydrive for second as follows: pinion 28 through sleeve F to gear 40thence through gears 31, 36 and 39 to sleeve 42 and shaft 20, the clutchE overrunning.

When driving in third, fourth or direct is obtained just as for secondby driver release of the accelerator pedal and resulting shift of sleeveF to clutch with teeth 49 when these parts are synchronized by reason ofthe engine coasting down from the drive in third. The direct drive is atwo-way drive as follows: pinion 28 through sleeve F to gear 40 thencedirectly through sleeve 42 to shaft 20, clutch E overrunning as abefore.

Referring to Figs. 4 to 9 there is shown the blocking means forcontrolling clutching shift of sleeve F so as to limit clutching thereofto engine coasting and synchronous relationship of the clutching parts.Sleeve F is provided with a seriesv of pairs of what may be termed longand short teeth 50, 5I certain of which may be bridged `or joinedtogether. A blocker ring 52 is provided with blocking teeth 53 whicheither lie in the path of forward shift of teeth 50 or 5I or elsebetween these teeth to allow clutching shift of sleeve F. Thus, blocker52 has, at suitable locations, a drive lug 54 engaged in a slot 55 ofgear 40. The blocker is urged under light energizing pressure of spring56 into constant frictional engagement at 51 with pinion 28 so that theblocker tends to rotate with pinion 28 within the limits afforded by thetravel of lug 54 circumferentially in slot 55.

During drive in first and third, the speed of shaft 21 exceeds the speedof gear 40 so that, if sleeve Fis fully released, the parts will bepositioned as in Fig. 5 wherein the blocker leads the sleeve F therebypositioning blocker teeth 53 axially in alignment with the short teeth5I. If now the sleeve F is urged forwardly it will move to the Fig. 6position of drive blocking and will remain in this blocked position aslong as the engine drives the car in first or third.

If now the driver releases the accelerator pedal so that the engine maycoast down under accommodation of overrunning clutch E, while sleeve Fis urged forwardly, then when pinion 28 is reduced in speed to that ofsleeve F slight further drop in speed of pinion 28 for a fraction of arevolution below the speed of sleeve F will cause blocker 52 to rotateslightly relative to sleeve F until blocker teeth 53 strike the adjacentsides of long teeth 50 as in Fig. 7 thereby limiting further reductionin speed of the blocker relative to sleeve F. At this time the sleeve Fis free to complete its forward clutching shift with teeth 49, as inFig. 8, the blocker teeth 53 passing between adjacent long and shortteeth 50, 5|. With the sleeve F thus clutched during engine coast, atwo-way drive is established in second or fourth depending on whetherthe manually shiftable sleeve F was set for first or third just prior tothe clutching shift of sleeve F.

In the event that sleeve F is urged forwardly from its Fig. 5 positionat a time when the gear 48 is rotating faster than pinion 28, then theblocker 52 will lag behind theA sleeve and will be blocked by engagementof long teeth 59 with the blocker teeth '53 as shown in Fig. 9. This isre terred to as the coast blocking condition. If now the engine isspeeded up by the driver depressing the accelerator pedal in the usualmanner, then the engine and blocker 52 rotate forwardly and blockerteeth 53 move over to the Fig. 6 drive blocking position thereby jumpingthe gap between teeth 50 and 5|. This is the primary reason forproviding the long and short teeth whereby sleeve F clutches only fromthe drive blocking condition followed by engine coast which protects theteeth and avoids harsh clutching effects on the passengers andtransmission mechanism'. On accelerating the engine from the Fig. 9coast blocking condition, the engine comes up to a speed limited byengagement of the overrunning clutch E for drive in either first orthird depending on the setting of the manually shiftable sleeve 42. Thenon releasing the accelerator pedalthe `sleeve F will synchronouslyclutch with teeth 49 during coast to'step-up the drive to either secondor fourth as aforesaid.

The transmission is provided with suitable motor means for controllingshift of sleeve F along with several control means. Referring particuularly to Figs. 10 and l1, there is illustrated a f pressure fluidoperated motor G utilizing air pressure for its operation. Forconvenience this motor is arranged to operate by the vacuum in theintake manifold system of the engine under control of electromagnetic`means illustrated in the form of a solenoid H.

Forward shift of sleeve F is effected, under vcontrol of motor G, byreason of a spring 58 fixed at one end andv exerting a pull on lever 59which is connected to sleeve F through the crosse shaft 50 and shifteryoke 0 I. Pivoted to the lower end of lever 59 is a follower rod 62guided in a support 83 and in the rubber4 sealing boot 64 carried bycylinder 65 which contains the diaphragm piston 65 urged in a directionto release sleeve F by a spring 61 which is much stronger than spring58. Diaphragm piston B6 is connected to a leader `rod 68 which has arear extension 69 aligned with rod 62.

Rod 68 has a series of detents, 10, 1| and 12, thelatter cooperating.with a latch 13 such that when vacuum is admitted to chamber 14 to causethe piston 66 and rod 68 to assume their Fig. 1l positions, latch 13under action of rat-trap spring 15 catches on the' forward shoulder ofdetent 12 and holds the parts as in Fig. 11. At this time rod portion 69moves further than rod 62 by the amount of gap 16, a stop 11 acting onlever v'59 limiting forward movement of sleeve F by spring 58.

In order to provide for release of sleeve F, it is desirable to providesome means for momentarily relieving the torque load at the teeth 49 andsleeve F and in the present instance I have provided such means as asystem of grounding the primary terminal of the usual distributer of theignition system whereby theA engine vignition may be momentarilyrendered ineffective thereby unloadingthe torque at sleeve FVsuiiiciently to insure its released by spring 61.. This ignitioninterrupting system is under control of an interruptor switch 18 whichis closed by plunger 19 and ball l80 whenever rod 69 moves between theFig. 10 and Fig. 11 positions by reason of the enlarged rod portionbetween detents 10, 1|. Detent 1| is so arranged that, with the parts asin Fig. ll and sleeve F clutched, rod 68 may move rearwardlysuiliciently to close gap'16 vat the lost-motion between rod portion 69and rod 82, this movement causing switch 18 to closev and ground theignition system whereupon spring 81 may then cause further movement ofrod 58 and rod 62 to release `sleeve F, the switch 18 then opening bydetent 10 torestore the ignition sy'stem. f f f The vacuum supply tochamber 14 is under control of electromagnet meansA in the form of asolenoid H which comprises an armature plunger having valving parts 8|,82. In Fig. 10 the solenoid I-I is energized thereby raising plunger 00against spring 83 to seat valve 82 and shut off the vacuum supply tochamber 14 and at the same time unseat valve 8| so as to vent-thischamber through passage 84, chamber 85 and vent passage 86.` When thesolenoid is de-ener gized then spring 83 lowers plunger 80 therebyseating valve 8| to shut off vent 88 and open valve 82 as in Fig. llthereby opening chamber 14 to the engine intake manifold K through passage 84, chamber 86', andr pipe 81.

, A certain lost motion is provided between plunger 80 and the inwardlybent finger 13' of latch 13 so that when the plunger moves down.. wardlythe 'latch may subsequently catch at detent 12 when vacuum `operatespiston 66, the 'parts then remaining in the Fig. 1l positionindependently of vacuum in chamber 14 until solenoid H is energized torelease' the latch and vent chamber 14.

j vIt is deemed preferable to provide a speed control on theenergization of solenoid H so as to insure automatic release of sleeve Fbelow a predetermined car speed and automatic engagement ofy sleeve Fabove a predetermined car speed. Whenever the car is in forward drivingcondivtion the manual sleeve 42 is either shifted rearwardly to the lowrange or forwardly to the high range so that by driving a governor fromthe countershaft 35 it is possible to provide a speed control operatedproportionate to the speed of travel of the car. Driven fromcountershaft gear 88 is a governor J of any suitable type, thisgovernor'operating a sleeve 89 outwardly along its drive shaft 90 as thecar `speed reaches a predetermined point, thel breakaway being under control of a detent 9| if desired.

The sleeve 89.has a shoulder 92 engaged by the swinging switch piece 93of the governor switch 94. When the car is stationary the detent 9| isengaged and switch 94 is closed. As the car accelerates the governoreventually reaches its critical speed and detent 9| releases therebycausing switch 94 to open. As the car slows down, the governor spring 95restores the parts to the Fig. 10 position and by proportioning thevarious parts it is obvious that switch 94 may be made to function atdesired speeds proportionate to car travel. As an example -of onearrange-r ment of governor operation andv gearing arrangement, thegovernor may be made to open Vswitch 94 during car acceleration in firstand third respectively at approximately 'I and l5 M. P. H. (miles perhour), the switch 94 closing on stopping ther car in direct and Isecondat approximately 7 and 3 M: P. H. respectively.

, The driver operated ignition switch is designated at L and comprises aconductor 95-which, inthe Fig, 10 position showing the switch on orclosed, electrically connects contacts 91 and 98. Contact 91 extends Abyconductor 99 to ammeter |00 and thence -by conductor |0| to the usualstorage battery |02 vand thence to ground |03. l Contact 98 has ayconductor |04 extending therefrom to the engine ignition system hereinshown in'part ascomprising coil |05 and distributer |06 having a primaryterminal |01.

A second'conductor |08 extends from contact 98 tothe solenoid H andthence by conductor I 09 to one terminal of ignition interrupter switch18, the other terminal extending by conductor I I to our timer controldevice M.

Branchingy from conductor |09 are two conductors ||I' and I2, the formerextending to governor switch 94 and thence to ground ||3. Conductor |I2extends to kickdown switch ||4 and thence to ground ||5. The switch ||4is normally open and is closed preferably by a full depression ofaccelerator pedal 50 acting through linkage I I6. When pedal 50 is thusdepressed, thelever ||1 which operates the engine throttle valve y| I8is positioned to fully open the throttle valve, lever I I1 having anupper extension which at such time closes switch ||4 to eiect a stepdownin the transmission from fourth to third or from second to rst.

The governor solenoid circuit is as follows: ground |03 to battery |02thence by conductor |0| to ammeter |00 and by conductor 99 to ignitionswitch L. From switch L this circuit extends through conductor |08 andsolenoid H and thence by conductors |09 and to switch 94 and ground 93.

The kickdown solenoid circuit is the same as the governor solenoidcircuit to conductor |09 whence this circuit extends by conductor ||2 tokickdown switch ||4 and ground ||5.

The engine ignition circuit is the same as the governor solenoid circuitup to the ignition switch L whence this circuit extends by conductor |04toicoil |05 and distributer |06.

The ignition groundingA circuit for rendering the ignition inoperativecomprises a grounding mal association with bi-metal member |22 and iselectrically connected between conductor I0 and member |22. From battery|02, preferably by way of switch L, a conductor |24 extends to aresistance |25 and thence to a iixed contact |26 so disposed that whenmember |22 is subjected to heatof the resistance |23, member |22 delectsand causes contact |2| to separate from contact |20 and to engagecontact |26. Resistance |23 is selected so that when current is passedtherethrough, according to the circuit to be described, the bi-metalmember |22 will deflect so as to cause contact |2| to snap from contact|20 to contact |26 in a predetermined time after closing the interrupterswitch 19. While this time may be varied according to the operationdesired andv according to the functioning of the particular transmissionemployed with timer M, I have found in practice that a time interval ofabout one second, for example, is desirablefor the illustratedmechanism.

The primary ignition grounding circuit under control of interrupterswitch 18 extends from the distributer |06 through conductor I |9 tocontacts |20 and |2| thence through bi-metal member |22, resistance |23and conductor |0 to interrupter switch 18.v From switch 18 thisgrounding circuit extends through conductor |09 and thence to a suitableground. In the illustrated arrangement this lground is provided eitherat ||5 through conductor ||2 and kickdown switch ||4 or else at;

||3 through conductor and governor switch 94.

In the-event that, for any reason, the interrupter switch 18 remainsclosed longer kthan the normal time required when rod 68 moves from itsFig. 11 to its Fig. 12 position, then bi-metal mem-v ber |22 operates tobreak the primary ignition grounding circuit by reason of contact |2|swinging over to contact |26 whereupon the ignition system is restoredto norma1 operation. If desired, the member |22 may be arranged to actto restore the ignition in advance of the normal stroke of rod 68. Also,if, when the parts are in the Fig. 11 position, the solenoid should beenergized while sleeve F fails to release its engagement with teeth 49,then instead of the ignition system being rendered inoperative as gap 16is taken up thereby closing switch 18 and ltendingto maintain theignition system inoperative, the ignition system is grounded only solong as it takes for resistance |23 to heat bi-metal member |22 causingthe primary ignition grounding circuit to be broken.

When contact |2| snaps over to contact |26 to restore the ignitionsystem, then the contact 2| remains in such position as long as theinterruptor switch 18 is closed, automatically returning to contact |20when switch 18 opens. Thisy is brought about by reason of establishingsuiiicient current through resistance |23 to maintain member |22 heatedwhen contact 2| snaps over to contact |26. At such time current flowsfrom battery |02 through conductor 0| ammeter |00 and conductor 99thence through switch Lto conductor |08, conductor |24, resistance |25and through contacts |26, 2| to the bi-metal-member |22, thence throughresistance |23, conductor ||0, switch 18 and to ground ||5 or ||3 justas for the primary ignition grounding circuit. Resistance |25 determinesthe current owing through the heater resistance |23, only a smallcurrent being ordinarily required such as .5 of an ampere for examplealthough this depends on the type of bi-metal member employed and theextent of thermal proximity thereto. This circuit which is establishedby contact 2| engaging contact |26, within a predetermined time afterclosing interrupterswitch 18, and the relationship of this circuit withthe system of control as a whole, comprises the subject matter of myinvention, the remaining features of novelty being claimed in theaforesaid parent applica-tion which is now copending in the name ofVictor E. Matulaitis. This circuit may be referred to as a secondaryignition restoring circuit and is preferably under control of theignition switch L so that there is no danger of leaving this circuitclosed when the car isparked. Contact |2| is in its selective engagementwith contacts |20 and |26 acts in the capacity of temperature orthermo-responsive switch "means in series with interruptor switch '|8for controlling both the primary ignition grounding circuit and thesecondary ignition restoring circuit. i

In the aforesaid Neracher et a1. application there is set forth certaincircumstances under which the transmission becomes locked-up withsleeves F and 42 clutched and under torque load, and with gap 16 takenup so as to render the engine ignition inoperative. With my inventionthe ignition system is automatically restored under such conditionsmaking it possible for the engine to operate and unload the teeth ofsleeve F so that the same may then be released by spring 61 therebyopening switch 18 and restoring the system to normal operation.

In the operation of the mechanism, the car at standstill and with theignition switch L. closed and the engine idling will cause the solenoidH to be energized as inV Fig. because governor switch 94 is closedthereby establishing the governor solenoid circuit. Cylinder 14 isvented and sleeve Fy disengaged. The driver shifts sleeve 42 to eitherthe high or low range and accelerates the car ordinarily above thecritical speed of governor J thereby causingv switch 94 to open to breakthe governor solenoid circuit. As vacuum builds up in the engine intakemanifold K, plunger 80 now. being lowered by spring I83 because' switch94 is operi, piston 66 will beoperated by vacuum thereby moving rod 68to itsFig'. 11 latched position. As soon as the driverallows the engineto coast, sleeve F will engageteeth 49 synchronously, to step-up thedrive -to either second or fourth al though the step-up will bedelayeduntil engine coast thereby enabling drive in the slower driving ratio offirst or third as longfas desired.

If the car is initially accelerated in first above the governor criticalspeed and the engine allowed to coast,'then vsecond will automaticallybecome operative. Then if the driver shifts sleeve 42 forwardly to thehigh range, third will of course be skipped andy fourth will be obtainedbecause sleeve F' will remain engaged.' Ordinarily, especially wherethe'car -is equipped with a fluid coupling B, the sleeve 42 may be leftrin its high range and all starts and stops made without furthershifting. This isy possible owing to slippagel in the fluid couplingwhen stopping the car for a traino light and is practicable because thefluid coupling'allows high engine torque for favorable car accelerationand because governor J directs a downs'hift ron bringing the car torest. 'I'hus there is automatically provided a favorabletorque-multiplying gearing for starting, as in third.

Whenever the car is driving in fourth or second above the governorcritical'speed, a rfull depression of the accelerator pedal will'causethe transmission tostep-down vto third oriirst, the transmission step-upback to fourth or second taking place on release of the acceleratorpedal with attendant synchronization of sleeve F with teeth 49 l sleevewhereupon the ignition is restored at de-v tent 10 and the enginequickly speeds up to yen'- gage overrunning clutch E for' establishingthe third or first driving ratiov depending yon the setting of sleeve 42prior vto the kick-down operation. Ori bringing the car to -astop when`sleeve F' is clutched asin fourth for example, the governor J opensgovernor switch 94 so as to deenergize solenoid H, vent chamberand-cause release of sleeve F so that the car will be started in third,assuming Athe manual sleeve 42 to be' .left in its forward high rangeshift position If the sleeve F should not release when gap 16 is takenup, orif for any reasonthe switch 18 remainsclosed longer than normal,then the timer device M will automatically function, within apredetermined time from the closing of interrupter switch 18, to breakthe primary ignition grounding circuit and to restore and maintain the.ignition system so long as switch 18 remains closed.

If desired, the relationshipof heating resistance element 123 andbi-metal member |22 may be such that contactl |21 moves over to contact|26 ahead of the normal restoring operation of switch 18 to its openposition when rod 68 moves between its Fig. 1()` and Fig. 11 positions.

I claim:

l. In a drive for a motor vehicle having an engine provided with anignition system; transmission means comprising change speed mechanismadapted for manipulation to change the vehicle speed ratio drive;electrical circuit means for rendering said ignition system inoperative;an .interrupter switch Yoperable to control said circuit means; meansoperable to effect said manipulation of said transmission means; meansfor operating said switch from a first position thereof to a secondposition thereof as an incident to operation of said transmissionmanipulating means for estabiisni'ng said circuit means;thermoresponsive switch means operable. from a rst position thereof to asecond position there of to open Vsaidcircuit means with saidinterrupter switch-in its said second position; and electrical'circuitmeans including said thermoresponsive switch means operating in responseto operation of `said thermo-responsive switch means to its said secondposition for maintaining n the first said circuit means open and tnesecond said circuit means closed Vas long as said interrupter switch isin its said second position.

2. In a drive for a motor vehicle having an engine provided with anignition system; transmission means comprisingchange speed mechanismadapted fory manipulation to change the vehicle speed ratio drive;electrical circuit means for renderingv said ignition systeminoperative;v

an interrupter switch operable to control said circuit means; meansoperable to effect said manipulation of said transmissionnieans; meansfor operating said switch from avfrst positiony thereof to a secondposition thereof as an incident to operation of said transmissionmanipulating means for establishing said circuit means;thermo-responsive switch means operable from a first position thereof toa second position thereof to open said circuit means With saidintei'rupter switch in itssaid second position; said circuit meansincludinga resistance in thermal association with said thermo-responsiveswitch means; and electrical circuit means including said resistanceadapted to operatey in response to operation oi' said thermo-responsiveswitch meansltoits said second position for maintaining the rst saidcircuit means open as ylong as` nism adapted for manipulation to changethe` vehicle speed ratio drive; electrical circuit means for` renderingsaid ignitionsystem inoperative;

an .interrupter switch operable to, control, saidv circuit. means.;means:operableA to .effect said manipulation of said transmission means;means for operating said switch from a iirst position thereof to asecond position thereof as an incident to operation of said transmissionmanipulating means for establishing said circuit means; said circuitmeans including thermo-responsive switch means and a resistancethermally associated therewith so constructed and arranged that saidthermo-responsive switch meansoperates to open said circuit means whensaid interrupter switch is in its said second position; and electricalcircuit means including said thermoresponsive switch means, theinterrupter switch, and said resistance, for maintaining the rst saidcircuit means open as long as said interrupter switch is in its saidsecond position.

4. In a drive for a motor vehicle having an engine; transmissionmechanism operable vto provide a drive from the engine to the vehicle,said mechanism including positively engageable drivecontrol elementscooperable for relative engagement therebetween to establish said driveand for relative disengagement to release said drive, said elements whenrelatively engaged being subject to thrust-transmission therebetweenduring said drive so as to resist relative disengagement thereof torelease said drive until said thrusttransmission is relieved; anignition system for said engine adapted to be interrupted to relievesaid thrust-transmission; thrust-transmitting means operable to urgerelative disengagement of said elements as aforesaid; grounding circuitmeans adapted, when completed, to ground said ignition system by causingcurrent iiow from said ignition system to ground, thereby effecting saidinterruption; control means operable to efiect completion of saidgrounding circuit means so as to accommodate relative disengagement oisaid elements by said thrust-transmitting means, normally automaticallyfollowed by opening of said grounding circuit means within apredetermined time interval in response to relative disengaging movementof said elements thereby to effect restoration of said ignition systemto normal operation; a thermo-responsive element interposed in saidgrounding circuit means; a secondary circuit adapted to be closed undercontrol of said thermo-responsive element for rendering said ignitionsystem operative; and means response to said iiow oi current throughsaid grounding circuit means beyond said time interval for causing saidthermo-responsive element to open said grounding circuit means andclosing said secondary circuit thereby to effect restoration of saidignition system to normal operation upon failure of said control meansto open said grounding circuit means; said secondary circuit acting,when closed as aforesaid, to cause said thermo-responsive element tomaintain said grounding circuit means open and said secondary circuitclosed.

5. In a drive for a motor vehicle having an engine; transmissionmechanism operable to provide a drive from the engine to the vehicle,saidV mechanism including positively engageable driventrol elementscooperable for relative engaget therebetween to establish said driveyand ative disengagement to release said drive,

' when relatively engaged being subon therebetween during t relativedisengagementV laid drive until said thrusted; anlgnition system for ,jIinterrupted lto relieve thrust-transmitting means operable to urgerelative disengagement of said elements as aforesaid; grounding circuitmeans adapted, when completed, to ground said ignition system by causingcurrent ilow, from said.

ignition system to ground, thereby eiecting said interruption; controlmeans operable to .effect completion of said grounding circuit means soas to accommodate relative disengagement of said elements by saidthrust-transmitting means, normally automatically followed by opening ofsaid grounding Vcircuit means within a predetermined time interval inresponse to relative disengaging movement of said elements thereby toeffect restoration of said ignition system to normal operation; saidgrounding circuit means including a thermo-responsive element and anelectrically energized heating element in thermal relationship with saidthermo-responsive element; a secondary circuit adapted to be closedunder control of said thermo-responsive element for rendering saidignition system operative; said flow of cur-l rent through saidgrounding circuit means beyond said time interval acting to energizesaid heating element so as to cause said thermo-responsive element toopen said grounding circuit means and close said secondary circuitthereby to effect restoration of said ignition system to normaloperation upon failure of said control means to open said groundingcircuit means; said secondary circuit including said heating elementsuch that, when this circuit is closed as aforesaid, saidthermo-responsive element acts to maintain said grounding circuit meansopen and said secondary circuit closed.

6. A control for an engine ignition system comprsing; an electricalgrounding circuit adapted, when closed, to ground said ignition systemby causing current to ilow from said ignition systemy to ground, therebyrendering said ignition system inoperative; an ignition interrupterswitch interposed in said grounding circuit; means norfmally operatingto momentarily close said interrupter switch for effecting momentarygrounding of said ignition system; said groundingcircuit includingthermo-responsive switch means; `a resistance thermally associated withsaid thermoresponsive switch means and so constructed and arranged as torespond tosaid current ow for causing said thermo-responsive switchmeans to open said grounding circuit when said interrupter switchremains closed longer than momentarily; and a second electrical circuitincluding said interrupter switch and said thermo-responsive switchmeans, said second circuit being 'closed by operation of saidthermo-responsive switch means in openinglsaid .grounding circuit, saidthermo-responsive switch means responding to current ilow in said secondcircuit for maintaining said second circuit closed and said groundingcircuit open. f

7. In combination with a shift member for `a variable speed transmissionfor internal combustion engines, an engine ignition system, a groundingcircuit for said ignition system including `a normally open switch, anormally closed switch, means responsive to initial movement of theshift member for closing said normally openswitch, heat-responsive meansfor opening the normally closed switch, heating means for theheat-responsive means energized by closure of theA normally open switch,and electrical circuit'means, including said heating means,automatically established as an incident to said opening ofisaidnormally closed switch for energizing said fheating means. l

8. In combination with a shift member for a variable speed transmissionfor internal combustion engines, an engine ignition system, a groundingcircuit for said ignition system including a normally open switch, anormally closed switch, means responsive to initial movement of theshift member for closing said normally open switch, heat-responsivemeans for opening the normally closed switch, heating means for the

